Design of Exhaust Vents in Automotive Air Conditioning Systems

There are two types of throttling systems in the passenger car air-conditioning system, namely the expansion cycle system and the hole tube system. Under the same working conditions, the operating pressures of the two types of systems are very different, and they must be valued and distinguished during maintenance. Expansion valve circulatory system is a traditional temperature control system, the main difference is that the expansion valve throttling device is different. It is suitable for being installed in an air-conditioning circulation system featuring a liquid storage device, an expansion valve, and an intake throttle valve, and is installed in a high-grade car. The main difference of the hole tube circulation system is the installation position of the hole tube and the accumulator, and it is mostly applied to mid- and low-end cars.

Room air conditioners are fixed in one location and have a special external environment with good heat insulation. Therefore, it is not possible to use the hot and cold heat required by the unit's air conditioning area to estimate whether the car can be hot or cold. The refrigeration load of the car air conditioner is much larger than that of the room air conditioner. Most of the air sent by the room air conditioner is from the return air in the room, and the proportion of fresh air introduced from the outside is small, which generally accounts for about 15% of the air volume. The sedan space is extremely narrow and the occupancies are relatively dense.

In addition to sufficient fresh air, except for a short period of rapid deceleration, 100% of fresh air must be used, that is, all the air sent from the air conditioner comes from outside. This must be equipped with a special exhaust outlet for a sealed car, or it will affect people's health.

In a non-independent passenger car air-conditioning system in which a refrigerating compressor is driven by a car engine through a pulley, the rotational speed of the engine is constantly changing, and the idle speed and the high-speed rotational speed are generally 4-5 times different, and the rotational speed of the compressor also follows. The difference is several times, which is very different from that of the refrigeration system in which the AC motor drags the compressor to a substantially constant speed.